Even the planned release of the nearly 400-page report quickly spiraled into a political battle Wednesday over whether Attorney General William Barr is attempting to shield the president who appointed him and spin the report’s findings before the American people can read it and come to their own judgments.

Barr scheduled a 9:30 a.m. news conference to discuss the report before providing redacted copies to Congress and the public. The news conference, first announced by Trump during a radio interview, provoked immediate criticism from congressional Democrats.

House Speaker Nancy Pelosi said Barr had “thrown out his credibility” and “the DOJ’s independence.” And Senate Minority Leader Chuck Schumer said, “The process is poisoned before the report is even released.”

“Barr shouldn’t be spinning the report at all, but it’s doubly outrageous he’s doing it before America is given a chance to read it,” Schumer said.

Hours before Barr’s press conference, Pelosi and Schumer issued a joint statement calling for Mueller to appear before Congress “as soon as possible.”

Trump himself was in a high state of alert ahead of the report’s release. He repeated what has become a near daily refrain of criticism of the Russia investigation using his favoured Twitter account. “PRESIDENTIAL HARASSMENT!” he wrote.

Justice Department spokeswoman Kerri Kupec said Barr would address the department’s interactions with the White House over Mueller’s report, whether executive privilege was invoked and the process Barr used to black out portions of the document.

He was to be accompanied by Deputy Attorney General Rod Rosenstein, who oversaw the investigation after Mueller’s appointment in May 2017. Mueller and team will not attend, special counsel spokesman Peter Carr said.

After the news conference, the report was to be delivered to Congress on compact discs between 11 a.m. and noon and then posted on the special counsel’s website.

Barr formulated the report’s roll-out and briefed the White House on his plans, according to a White House official who was not authorized to discuss the matter publicly. The White House declined to comment on an ABC News report that it had been briefed on the contents of Mueller’s report beyond what Barr has made public.

At a later date, the Justice Department also plans to provide a “limited number” of members of Congress and their staff access to a copy of the Mueller report with fewer redactions than the public version, according to a court filing.

The report was expected to reveal what Mueller uncovered about ties between the Trump campaign and Russia that fell short of criminal conduct. It was also to lay out the special counsel’s conclusions about formative episodes in Trump’s presidency, including his firing of FBI Director James Comey and his efforts to undermine the Russia investigation publicly and privately.

The report was not expected to place the president in legal jeopardy, as Barr made the decision that Trump shouldn’t be prosecuted for obstruction of justice. But it is likely to contain unflattering details about the president’s efforts to control the Russia investigation that will cloud his ability to credibly claim total exoneration. And it may paint the Trump campaign as eager to exploit Russian aid and emails stolen from Democrats and Hillary Clinton’s campaign even if no Americans crossed the line into criminal activity.

The report’s release provides a test of Barr’s credibility as the public and Congress judge whether he is using his post to protect Trump.

Barr will also face scrutiny over how much of the report he blacks out and whether Mueller’s document lines up with a letter the attorney general released last month. The letter said Mueller didn’t find a criminal conspiracy between the Trump campaign and the Russian government but he found evidence on “both sides” of the question of whether the president obstructed justice.

Barr has said he is redacting grand jury and classified information as well as portions relating to ongoing investigations and the privacy or reputation of uncharged “peripheral” people. But how liberally he interprets those categories is yet to be seen.

Democrats have vowed to fight in court for the disclosure of the additional information from the report and say they have subpoenas ready to go if it is heavily redacted.

House Judiciary Chairman Jerrold Nadler, D-N.Y., joined the chairs of four other House committees in calling for Barr to cancel his news conference. But Rep. Doug Collins of Georgia, the ranking Republican on the Judiciary Committee, defended Barr and accused Democrats of “trying to spin the report.”

Collins said Barr has done “nothing unilaterally,” saying he had worked with Rosenstein and Mueller’s team “step by step.”

Mueller is known to have investigated multiple efforts by the president over the last two years to influence the Russia probe or shape public perception of it.

In addition to Comey’s firing, Mueller scrutinized the president’s request of Comey to end an investigation into Trump’s first national security adviser, his relentless badgering of former Attorney General Jeff Sessions over his recusal from the Russia investigation and his role in drafting an incomplete explanation about a meeting his oldest son took at Trump Tower with a Kremlin-connected lawyer.

Overall, Mueller brought charges against 34 people — including six Trump aides and advisers — and revealed a sophisticated, wide-ranging Russian effort to influence the 2016 presidential election. Twenty-five of those charged were against Russians accused either in the hacking of Democratic email accounts or of a hidden but powerful social media effort to spread disinformation online.

Five former Trump aides or advisers pleaded guilty and agreed to co-operate in Mueller’s investigation, among them Trump’s campaign chairman, national security adviser and personal lawyer.